Filter

ABSTRACT

A filter comprising a housing, which consists of at least two housing parts, and a filter element attached inside the housing. The invention provides for at least one latch element by means of which a detachable latched connection can be established between the filter element and at least one of the housing parts.

The invention relates to a filter and a filter element.

Such filters and filter elements are disclosed, for example, in DE GM296 16 834 in which a filter insert is shown whose ends are joinedsealingly to end plates, wherein one or both end plates have an opening,in the marginal area of which an annular gasket is placed, which whenthe filter insert is in the installed state cooperates with a portion ofthe filter housing, and wherein at least one of the end plates isconfigured with a collar-like extraction handle which is spaced axiallyoutward from the plane of the end plate and has an outside diametersmaller than the outside diameter of the end plate.

Also known from EP A1 0711 587 is a filter insert of this kind in whicha collar-like elevation is likewise shown on one of the end faces of thefilter insert, by means of which it is possible to remove the filterinsert from the housing.

Furthermore, DE-OS 43 33 151 discloses a locking mechanism near the tipfor a typewriter, in which three sleeve parts—a centering sleeve, ahandle sleeve and an inner sleeve—are nested one inside the other, whilea front pivot bearing is provided which resides between the handlesleeve and the centering sleeve, and forms a rotating latch and releasemechanism between the rear end portion of the centering sleeve and theaxially fixed and non-rotatable inner sleeve, the handle sleeve beingaxially displaceable on the outside of the inner sleeve.

If it is desired to use such filters or filter elements so that they areremovable from the housing without coming in direct contact with thefilter element, it is a disadvantage that the handle elements, which arecollar-like, are attached directly to the filter element, so that directcontact with the filter element is unavoidable. An additional devicecould be provided which clutches the filter element tong-wise in thearea of the collar-like shape. This has the disadvantage, however, thatan additional cost-involving device must be created in order to avoiddirect contact with the filter element.

The invention is thus addressed to the problem of improving a device ofthe kind described above so that a filter and filter element will resultwhich makes it easier to install and remove a filter element that canstill operate securely, without coming in direct contact with the filterelement.

The problem is solved according to the invention by a filter whichcomprises a housing consisting of at least two housing parts, and afilter element fastened in the housing; at least one latch means isprovided whereby a releasable latch fastening can be produced betweenthe filter element and at least one of the housing parts. The advantageof such a solution is that a filter cartridge can be inserted into andremoved from a filter housing in which the cartridge is fastenedpositively to a housing part without coming directly in contact with thecartridge which is possibly contaminated after use.

An advantageous embodiment of the invention provides that at least onelatch means engages at least one corresponding opening and becomeshooked therein in the manner of a bayonet. This has the advantage thatdefinite locations are created at which a detent, for example, can enterinto a reliable and yet releasable connection.

In another advantageous embodiment, at least one latch means is disposedon the filter element. The latch means provided on the filter elementresiliently engages in a corresponding recess on the housing in order toproduce a releasable snap fastening.

Also, provision can be made according to the invention for at least onelatch means to be provided on at least one housing part. As a reversalof the action, the placement of the latch means on the housing is alsopossible.

In an advantageous embodiment of the invention, at least onecorresponding recess is provided on at least one housing part. Theserecesses provide the assurance that the engagement and disengagementwill definitely take place, especially disengagement when the filterelement is to be removed from the housing. In this case an axialmovement of the filter element is provided for, whereby a conversion ofthe axial movement to a rotation brings the filter element inside of therecess to a position which makes it possible to bring the filter elementout of the housing part contrary to the movement originally applied tothe filter element.

In another advantageous embodiment, at least one corresponding recess isprovided on the filter element. As a reversal of the action, theplacement of the recess also on the filter element is possible.

Also according to the invention the recess can have a closing range, anopening range, a translation range, a retaining range and a releaserange. In this case the recess is configured such that an area ispresent which, after the filter element has been snapped into thehousing part, provides so that the filter element is securely guided inthe housing part by the cooperation of the latch element with thecorresponding closing range of the recess until the housing is closed.

Embodiments of the invention are represented in the drawings and areexplained hereinbelow.

FIG. 1a is section through a filter,

FIG. 1b a section through the housing cover from FIG. 1,

FIG. 1c a development of the recess geometry in the housing cover,

FIG. 1d another variant of a development,

FIG. 2a a section through a filter,

FIG. 2b a section through a filter element,

FIG. 3a a section through a filter,

FIG. 3b a section through a filter,

FIG. 3c a section through a filter,

FIG. 3d a section through a filter.

In FIG. 1a a section taken through a filter is shown, which has ahousing 1 which in turn consists of two housing parts 2 screwedtogether. The filter with its housing contains in addition to an inletand outlet for the fluid, not shown, a hollow cylindrical filter element3 on the end of which latch means 4 are provided, which serve for alatch connection 5 between filter element 3 and housing part 2, andespecially with the cover of the housing. The filter element 3 is shownin two assembly positions in this embodiment, on the left in thepre-assembly position, and on the right in the final assembly position.To produce a reliable latch connection a recess 6 is created in the areaof the cover of the housing part 2 of housing 1. This recess 6 hasdifferent function areas which are necessary for producing and releasingthe latching action. The function areas are made up of closing, opening,translation, retention and release areas.

The filter element 3 is fixed in the receiver 17 by means of a seal 16and seals the clean fluid side from the raw fluid side. The filterelement can be installed in two ways. In one, there is the possibilityof placing the filter insert 3 on the receiver 17 and then screwing thefilter to the second housing part by means of screw thread 18, thesecond housing part performing a movement during the screwing operationtoward the filter insert 3 situated in the housing. As the housing partmoves toward the latch means 4, the latch means 4 must overcome aretention area 10 which, due to the simultaneous rotatory movement ofthe housing part, brings the result that the latch means in theembodiment using four latch means and corresponding recesses regularlydistributed on the circumference snaps into the recess provided for itno later than after a quarter turn of the cover and forms a reliablelatched connection 5 in the case of the inverse opening. In anotherinstallation variant, the filter insert 3 is to be inserted directlyinto the cover part of the housing 1 with the recesses 6, so that alatched connection results between the filter element 3 and the housingpart 2. The parts joined together can then be inserted with one handinto the lower housing part 2 and on its receiver 17. The two housingparts 2 are then joined together by means of screw thread 18.

FIG. 1b is a section from FIG. 1a in the area of the cover and housingpart 2. Here it can be seen that the recess 6 has different functionareas. In this figure the translation area 9 and the retention area 10are to be seen.

FIG. 1c shows a development of the area of housing 2 that has beenrepresented in FIG. 1 b. On the entire circumference of the cylindricalsurface can be seen four recesses 6 arranged at regular intervals. Eachrecess 6 has in its bidimensional development the shape of an impressednumeral 1. Each recess 6 is divided into specific function areas. If thetwo housing parts are screwed together, the latch means 4 are placedagainst the closing area 7 of the recess 6. The retention area 10 of therecess 6 has the purpose of leaving the filter insert 3 in the coverhalf of the housing part when it is removed so that both parts can betaken out with one hand. In order then to separate the filter element 3from the housing part 2 with the recesses 6, without having to useanother hand to help, a translation area 9 is provided in the recess 6,which, with respect to the upper horizontal definition of the housingpart, has an angle of 30 degrees or between 30 and 90 degrees. Onaccount of the translation portion 9 provided in the recess 6 it ispossible by a vertical movement imparted abruptly along the housing andfilter element axis to produce a relative rotation between filterelement 3 and the housing part with the recesses 6 and latch means 4 andrecesses 6. By this relative movement, caused for example by a verticalstriking of the inner edge of the filter element 3, or by a simpleturning of the filter element 3 against the housing part 2, the latchmeans 4 enter into the opening area 8 of the recesses 6. In the openingarea 8 of the recesses 6 the retention area 10 is interrupted, so thatthe filter element together with its latches 4 drops without resistanceout of the housing part 2, which contains the recesses 6.

In FIG. 1d there is shown a variant of the recess 6 with a pronouncedretention area 10. Also indicated by a broken line are the latch means4. The recess 6 furthermore has a closing area 7 as well as an openingarea 8 and a translation area 9.

In FIG. 2a are shown two variants. In variant I the cartridge insertionsituation is shown, and variant II shows the cartridge removalsituation. In the section taken through the filter that is shown, whichincludes the housing 1 which in turn consists of housing parts 2 andcontains a filter element 3, the detailed representation of the joiningof the housing parts is omitted, since this has already been made in thefigures described above. This figure shows how the latch means 4 entersa releasable junction 5 with the communicating elements, such as therecesses 6, for example, which are disposed in the sleeve 12 and thehousing part 2. In the form represented in variant I, after the filterelement 3, with sleeve 12 installed, has been inserted into the housingpart 2, a snap fastening 5 exists, which retains the filter element 3securely in the housing part 2, for which the positioning of the latchmeans 4 shown in this variant with respect to the retention area 10 isresponsible. In the embodiment shown in variant II the releasing of thelatch junction 5 is disclosed, the latch means 4 being brought to aposition in which they become positioned radially inwardly, such thatthey are held there in a release area 11 which is situated in the sleeve12 located above and around the latch means 4. To enable the latch means4 to be driven into this release area 11, the sleeve 12 must be moved,with respect to the longitudinal axis of the filter element 3, alongthis axis toward the filter element 3, to such an extent that the latchmeans 4 can snap in at that point. This is accomplished by a axialmovement of the housing part 2 along its own longitudinal axis towardthe filter element 3, if the distance reducing element 13 on the sleeve12 and the distance reducing element 14 are axially one above the otheron the housing part 2. This positioning of the distance reducingelements 13 and 14 with respect to one another when the housing part 2is screwed on can be accomplished by the abutment of the distancereducing elements 13 and 14 in the circumferential direction. If now thelatch means 4 are engaged in the release area 11 in this manner, thefilter element can be taken out of the housing part 2 without resistancepast the retention area 10. The spacing and centering pin 15 serves as apressure element in the installation of the filter element 3.

In FIG. 2b there is shown a filter element 3 which has at its one endlatch means 4 acting resiliently in the radial direction. At the sameend a spacing and centering pin is provided in the longitudinaldirection of the filter element, which represents an alternativereversal of the principle described in FIG. 2a. This is also conceivablewith regard to the arrangement of the latch means, since in a reversalof the action, they could also be fastened to the housing part 2. Asleeve 12 is passed around and over the latch means and the latch meanscan come to rest in its recesses 6, projecting radially outward beyondthe imaginary circumferential surface of sleeve 12. A distance reducingelement 13 is disposed on the outside of the end of the sleeve and, asdescribed above, serves for releasing the latch connection.

In FIGS. 3a to 3 d different variants are represented. In the variantsin FIGS. 3a to 3 c the cartridge installation is shown, in which asimple, resistance-free removal of the filter element is possible, witha secure latch connection. In the sections shown in FIGS. 3a to 3 c,taken through the filter, which includes the housing, which in turnconsists of housing parts 2 and contains a filter element 3, there isshown the releasable latch connection 5 produced by the latch means 4with the communicating elements, such as the recesses 6 which aredisposed in the sleeve 12 or the housing part 2. In the form representedin FIG. 3a, after the filter element 3 has been inserted into thehousing part 2, a latch connection 5 exists, which holds the filterelement 3 securely in the housing part 2, and for which the positioningof the latch means 4 with respect to the retention range 10 isresponsible. By the arrangement of the distance reducing elements 13 and14 such that they are not in direct axial contact in FIGS. 3a to 3 c, itis clear that in no position of the housing (FIGS. 3a to 3 c) can thelatch fastening 5 be released by pulling force on the cartridge, and thespacing and centering pin limits the freedom of movement of the housing.

In the drawing shown in FIG. 3d, the release of the latch fastening isdisclosed, while the latch means 4 are brought into a position whereinthey are positioned radially inward such that they latch in a releasearea 11 which is disposed in the sleeve 12 around the latch means 4. Sothat the latch means 4 will be able to arrive in this release area 11the sleeve 12 must be moved with respect to the longitudinal axis of thefilter element, along this longitudinal axis to the filter element 3, tosuch an extent that the latch means 4 can snap into it. This isaccomplished by an axial movement of the housing part 2 along its ownlongitudinal axis to the filter element 3 when the distance reducingelement 13 on the sleeve 12 and the distance reducing element 14 on thehousing part 2 are axially one over the other. This positioning of thedistance reducing elements 13 and 14 with respect to one another whenthe housing part 2 is screwed on can be accomplished by an abutment ofthe distance reducing elements 13 and 14 in the circumferentialdirection. If now the latch means are caught in the release area 11 inthis manner, the filter element can be removed from the housing part 2without resistance past the retention area 11. The function of thespacing and centering pin as a pressure element during assembly can alsobe provided by the hooked edges of the retention area 10 and the latchmeans 4.

What is claimed is:
 1. A filter assembly comprising: a housing having a first part and a second part; means for rotatably connecting and disconnecting the first part to the second part; a filter element configured to fit in said housing; a latch connected to one end of said filter element for attaching said filter element to said first housing part; said first housing part including a recessed portion for receiving said latch wherein said recessed portion has a closing area which accommodates the latch upon rotatably connecting the first and second parts of the housing and wherein the recessed portion also including a retention area for retaining said latch upon rotatable disconnecting of said first and second parts of the housing and after the separation of said first and second parts of the housing, said recessed portion further having a translation area having an inclined surface for separation of said latch from said retention area and said recessed portion having an opening area for providing a resistance free separation of said latch from said recessed portion in order to separate said filter element from said first part of said housing.
 2. The filter assembly according to claim 1, wherein said closing area of said recessed portion further includes a connection device for retaining said latch when said first and second parts of said housing are not completely connected.
 3. Filter assembly according to claim 1, wherein said means for a rotatably connecting the first and second parts of said housing include a screw thread.
 4. A filter assembly comprising: a first housing having a first and second part, wherein said first part includes a recess defining area; a filter element configured to fit in said housing; a latch means connected to said filter element to provide a releasable connection between said filter element and the retention area of the recess of said first housing part; a sleeve disposed within said recess and surrounding said latch means wherein said sleeve and said recess cooperate to permit a connection between said latch means and said retention area in a first position, said sleeve and said recess including distance reducing elements, said sleeve defining a releasing area for permitting release of the connection between the latch means and said retention area when said distance reducing elements are positioned in an abutting relationship to move said sleeve to a second position in order to provide resistence-free separation of said filter element and said housing. 